1. Field of the Invention
The present invention relates to an information storage apparatus, and more particularly, to an information storage apparatus that identifies unrecorded regions of a recording medium and selectively stores data in the unrecorded regions.
2. Description of the Related Art
In the case of rewritable recording media such as CD-RW (Compact Disk-ReWritable), DVD-RAM (Digital Versatile Disk-RAM), DVD−RW (Digital Versatile Disk-ReWritable), DVD+RW (Digital Versatile Disk+ReWritable), an information storage apparatus conventionally certifies a region of the recording medium by storing dummy data in the region before the information storage apparatus stores user data in the region of the recording medium in random access mode.
The information storage apparatus writes dummy data in the region of the recording medium and reads the dummy data in order to check whether the region of the recording medium contains any defects. If the region of the recording medium is defective (contains any defect) but the positions of the defects in the recording medium are known in advance, the information storage apparatus can avoid writing user data on the defective positions so that the user data are not lost.
The recording medium also needs to be certified to fill unrecorded regions of the recording medium with dummy data so that a read only apparatus such as a CD drive and a DVD drive can read the recording medium. A rewritable apparatus can read data even if the data are written in the recording medium at intervals, but the read only apparatus such as a conventional CD drive and a conventional DVD drive may fail to read data written in the recording medium at intervals because the unrecorded regions cause the read only apparatus to malfunction.
Additionally, if the quantity of data written in the recorded region is less than a predetermined size, the read only apparatus may erroneously access the unrecorded region and fail to normally operate. Accordingly, the rewritable apparatus needs to certify the recording medium so as to avoid the above problems.
Japanese Laid-open Patent Application No. 5-114247 discloses a magneto-optical disk drive that can efficiently use information about defects detected during its manufacturing process by a disk certifying system and, if user data are relocated during a writing operation, smoothly check the reason of the relocation.
According to the specification of the above patent application, the magneto-optical disk drive includes a means for reading the address of defective positions identified by the disk certifying system. The disk has a zone located in the edge of the disk in which the address of the defective region is to be recorded. The magneto-optical disk drive further includes a means for recording the address of the defective positions in the zone. Accordingly, the magneto-optical disk drive retrieves, while it is formatting the disk, the information of defective positions identified by the disk certifying system and records the addresses of the defective positions in the zone.
However, according to the related art of the certifying operation, if the quantity of data recorded in a disk is too small, a disk drive has to write additional data until the quantity reaches a certain quantity so as to make the disk readable by a read only apparatus. Additionally, when the disk drive writes dummy data in the unrecorded region, the disk drive needs to not only write data in the unrecorded region but also overwrite recorded data in the recorded region. A user has to wait for long until the disk drive completes certifying the disk.
In the case where there are recorded regions and unrecorded regions in a disk and/or the size of data recorded in a recorded region is equal to or greater than a certain quantity, another disk drive such as a conventional read only apparatus may not able to read the disk due to lack of compatibility.
According to the conventional formatting disclosed in Japanese Laid-open Patent Application No. 5-114247, a whole disk needs to be certified. The user has to wait for long for the disk drive to complete writing dummy data in the whole disk and reading the dummy data from the whole disk.